Model of an atom



FIG. 1 is a perspective view of a model of an atom showing my new design;

FIG. 2 is a front side view thereof;

FIG. 3 is a rear side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof. 

CLAIM The ornamental design for a model of an atom, as shown and described. 